System for handling surface-finishing layers in the production of pressed board

ABSTRACT

A mechanism for manipulating cover layers for pressed board in which a carriage is shiftable along a track above a transport path for the layers and entrains a movable support therealong and at least two clamps carried by the support and engageable with opposite edges of the cover layers. The clamps each comprise a fixed jaw, preferably of wood, mounted upon the support and a swingable jaw, preferably also of wood, adapted to engage the cover layers from below and retain them against the respective fixed jaw.

United States Patent 1 Posselt June 3, 1975 SYSTEM FOR HANDLING SURFACE-FINISHING LAYERS IN THE PRODUCTION OF PRESSED BOARD [75] Inventor: Manfred Posselt, Viersen. Germany [73] Assignee: G. Siempelkamp & Co., Krefeld,

Germany 221 Filed: Feb. 28, 1973 21 Appl. No.: 336.734

[30] Foreign Application Priority Data Mar. 1, 1972 Germany 2209691 [52] US. Cl. 214/1 BB; 294/81 R [51] Int. Cl. B666 H22 [58] Field of Search 294/81 R, 81 SF, 67 BC, 294/67 DB, 62; 214/1 BB, 8.5 A, 8.5 C, 8.5 SS, 6 A

[56] References Cited UNITED STATES PATENTS 113,799 4/1871 Rugg 294/6 2 1,510,886 10/1924 Fuller 214/6 AX 1,710,096 4/1929 Luce .1 214/6 A 3,241,686 3/1966 Hurst 294/81 SF 3,665,655 5/1972 Klein 3,731,785 5/1973 Stuart 214/1 BB X FOREIGN PATENTS OR APPLICATIONS 1,058,331) 2/1967 United Kingdom 294/67 BC Primary Examiner-Albert J, Makay Assistant ExaminerGeorge F. Abraham Attorney, Agent, or Firm1(ar1 F. Ross; Herbert Dubno [57] ABSTRACT A mechanism for manipulating cover layers for pressed board in which a carriage is shiftable along a track above a transport path for the layers and entrains a movable support therealong and at least two clamps carried by the support and engageable with opposite edges of the cover layers. The clamps each comprise a fixed jaw, preferably of wood, mounted upon the support and a swingable jaw, preferably also of wood, adapted to engage the cover layers from below and retain them against the respective fixed 2 Claims, 11 Drawing Figures m5; w nd-am 3 I975 3,887,082

SHEET 3 Transparent Protective Layer Decorative web Moisture barrier Wood- Fiber Mat FIG.5 F|G.6

FIG.7 FIG.8 FIG.9

SYSTEM FOR HANDLING SURFACE-FINISHING LAYERS IN THE PRODUCTION OF PRESSED BOARD FIELD OF THE INVENTION My present invention relates to a mechanism for manipulating cover layers for application to a pressedboard body and, more particularly, to a system for applying cover layers to a mat, prepressed layer or other body in order to improve the surface characteristics thereof after a final pressing operation.

BACKGROUND OF THE INVENTION In the production of pressed board, it has become a common practice to provide finishing or surfaceimprovement layers to one or both outer faces of a core of fibers, chips or other comminuted wood or eellulosic structure to alter the appearance, texture, moistureresistance or weathering characteristics of the pressed board. For example, the resistance of the pressed board to moisture penetration may be improved by applying a moisture barrier, a sealing layer, or some other foil, web or sheet impermeable to moisture onto the unpressed mat of loosely coherent fiber materials, to a prepressed mat of such material or even to a fully com pressed bonded mat. The surface-finishing layer is then laminated to the substrate, generally under heat and pressure.

Where the pressed board is to have a predetermined texture different from that of the pressed wood fibers, it is not uncommon to provide a decorative or texturing layer, e.g., of paper printed with the desired pattern, and to cover the printed layer with a finishing layer which is transparent and impervious to moisture. The decorative or texturing layer may also be a metal foil, a metallized-paper foil or the like which itself is impervious to moisture.

These layers, and others known in the art, are hereinafter described as surface-finishing layers. As noted, they are generally applied under pressure in a final pressing step, frequently together with the application of heat, to bond the surface-finishing layers to one another and to the substrate which may have been preformed or is rendered coherent by the pressing operation during which the foils, webs, sheets or layers are bonded to one another and to the substrate.

The pressed board may be composed of wood fibers, chips or dust, of cellulosic fibers or of fibers obtained as waste products from the treatment of agricultural residues or the like and may be bonded under heat and pressure using naturally occurring thermoplastic and thermosetting resins or thermosetting resins which are added to the mass during a mat-forming operation. A typical example of pressed board is a layer of wood fibers to which a phenol-formaldehyde, urea, resorcinol or like thermosetting binder is added. The particulate mass and the binder may be applied to a conveyor belt in the layer-forming step, or the fibers may be formed upon charging trays adapted to carry the layer into a platen press. When the layer is formed upon a conveyor-belt system, so-called conveyor tablets may be used to dispose the mats one above the other for simultaneous charging of a multiplaten press therewith. The mats may be shaped and separated from one another and may even be subjected to prepressing, e.g., in a sin gle-platen press, before being ultimately charged into the multiplaten press.

The surface-finishing layers described above may be applied at any point to the mat and may pass with this mat into a multiplaten press of the heated-platen type for final bonding of the body into a rigid. structurally strong sheet.

The finished sheet may have a wide range of densities, depending upon the temperature and pressure of the final pressing step and the proportion of binder added and the ultimate use of the sheet will depend upon the density and like factors. For example, when the finished sheet is to have maximum thermal and acoustical insulation characteristics, it will generally be less dense and more porous. Where the sheet is to have greater rigidity and hardness, it will usually be more dense.

When surface-finishing foils are applied to fiber mats or prepressed fiber substrates for bonding thereto, it is common to apply a moisture-barrier layer, generally referred to simply as a barrier layer or barrier paper" to the substrate. One may also apply to the barrier layer a decorative layer or paper supplying the desired aesthetic pattern, and a final or protective layer or paper, generally described as an overlay paper," so that the surface-finishing layer actually consists of at least theee sheets or papers and possibly more. depending upon requirements.

In earlier systems for applying the layers, it was generally necessary to convey each layer by a suction head or the like to a gathering station at which the substrate was disposed or at which a support for the substrate was disposed so that each layer could be applied individually by suction lifters or conveyors to the substrate or the support. When the correct number of layers was applied to the substrate, the latter could be charged into the multiplaten press. Alternatively, once a proper number of layers had been gathered at a receiving surface, the mat was deposited thereon and the laminate structure fed into the platen press.

These systems had disadvantages because the stack of layers could not be effectively applied in a single operation and consequently the process involved a considerable amount of manual labor.

OBJECTS OF THE INVENTION It is the principal object of the present invention to provide an improved system for handling multilayer stacks of surface-finishing materials for application to pressed board.

Another object of the invention is to provide a mechanism for the purpose set forth in which the amount of manual labor can be reduced.

SUMMARY OF THE INVENTION These objects and others which will become apparent hereinafter are attained, in accordance with the present invention, with a transport carriage provided with a support and a pair of clamps mounted on the support and shiftable with the carriage from a position in which the support is disposed above a pickup table to a position in which the support is disposed above a receiving surface.

According to the invention, the clamping means is adapted to straddle opposite sides of the table which is of a smaller outline than the stack of surface-finishing layers deposited thereon by any conventional collating means.

Opposite edges of this stack are gripped by pairs of clamp jaws overhanging the edges of the table. preferably along the longitudinal edges thereof and the longitudinal edges of the rectangular stack of surfacefinishing layers. The clamping means preferably comprises a fixed jaw mounted on the support and disposed inwardly of the longitudinal edges of the layer stack or the rectangular plan thereof while the otherjaw of each clamp is swingable relative to the support, preferably about a horizontal axis parallel to the aforementioned longitudinal edges to enable the lower jaw to clear the longitudinal edge of the lower stack when the support is lowered. The clamping means also comprises means for shifting the lower jaw perpendicularly to its longitudinal direction, i.e., in a direction which is transverse to the longitudinal edge so that each lower jaw bears upon the respective marginal portion of the layer step from beneath and clampingly retains it against the upper jaw.

The invention is based upon the recognition that stacks of a number of the aforementioned papers can, with the use of the aforementioned clamping means. be manipulated, i.e., lifted, transported and lowered, without difficulty and without the disadvan tage of individual-sheet manipulation as has hitherto been necessary by reason of the use of suction devices or the like. The system has been found to be most advantageous where each of the clamping jaws is a bar extending over a substantial portion and preferably the entire length of the longitudinal edges of the stack.

It will be self-understood that the clamping force should be so adjusted that the surface'finishing layers are not damaged and I have found that when the clamping bars are formed from wood, a wide range of clamping pressures may be applied without damage to the foils. The swinging displacement of the movable clamp jaw, according to the present invention. ensures that the movable jaw will Clear the longitudinal edges of the foil stack and consequently not engage the latter when the support is lowered. Of course, some other force absorbing or cushioning member, e.g., of foam rubber, may be applied to the engaging faces of the jaws or may constitute the latter.

DESCRIPTION OF THE DRAWING The above and other objects, features and advantages of the present invention will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIG. I is a diagrammatic side-elevational view of an apparatus, according to the present invention. about to pick up a stack of surface-finishing Sheets;

FIG. 2 is a bottom view of the apparatus, showing the table in broken lines;

FIG. 3 is a view similar to FIG. 1 illustrating the stack in its elevated position prior to movement onto a conveyor tablet;

FIG. 4 is a view similar to FIG. 1 showing the stack of about to be deposited upon a conveyor tablet according to the present invention;

FIG. 5 is a cross-sectional view through a portion of a board, about to be pressed, as it is disposed upon a press-charging plate;

FIG. 6 is a view similar to FIG. 5 illustrating another arrangement;

oil

FIG. 7 is a detail view, drawn to an enlarged scale for an apparatus for swinging the movable clamp means of FIGS. 1-4;

FIGS. 8 and 9 are respectively a front and a side elevational view showing the clamping members, partly in cross-section.

FIG. 10 is a detail view illustrating the means for vertically displacing the supports in FIGS. 1 4; and

FIG. 11 is a detail view of a conveyor tablet adapted to deposit the stack of foils, sheets or layers onto a mat which, in turn, deposits the mat between the platens of a multiplaten press.

SPECIFIC DESCRIPTION Referring first to FIGS. 5 and 6, it will be seen that the present invention relates to the manipulation of stacks 24 or 34 of surface-finishing papers, sheets, foils or layers which can be applied to the upper or lower surface of wood-fiber, wood-chip or sawdust mat or layer as represented at 20 or 30.

The layers may include an inner moisture-barrier layer of metal foil or synthetic resin, the underside of which may be coated with a thermally activatable adhesive or which may be bonded by the binder of wood mat to the latter. The moisture barrier layer is represented at 21 and 31 in FIGS. 5 and 6. Outwardly of the moisture-barrier layer there is provided a decorative paper or web 22, 32, the underside of which may be provided with a layer of a thermally activatable adhesive or, alternatively, either moisture-barrier layer or the decorative web layer may be formed in part of a thermally activated adhesive designed to bond the two layers together simultaneously with the bonding of the moisture barrier layer 21 or 31 to the wood-fiber mat 20 or 30. Overlying the decorative web 22, 32, there is provided a transparent protective layer 23, 33 which is exposed to the elements and may consist ofa syntheticresin resistant to attack by weathering and serving to prevent abrasion of the decorative paper therebelow. Again the decorative web may include a thermally activated adhesive, the transparent protective layer 23, 33 may include such a material, or a separate adhesive layer may be provided between the two. When the stack is applied to the mat 20 and the latter is disposed on the press-charging tray 5', the surface-finishing operation occurs only on one surface of the mat. However, when the stack is initially deposited upon the press-charging plate 5', the fiber mat 30 and another stack 24 can be applied thereto (FIG. 6). The present invention is primarily directed at manipulating stacks 24 and 34.

Referring then to FIGS. 1 4, it will be seen that the stack 1 of surfacefinishing layers (FIGS. 5 and 6) for the production of decorative chipboard, fiberboard and the like, is collated upon a table 4 of a width less than the width of the stack so that the stack overhangs the table 4 (FIG. I).

The apparatus comprises a carriage 2 which is shiftable along a track 6 and is provided with means (FIG. I0) for vertically raising or lowering the support 3 of the pickup device which has a rectangular outline as illustrated in FIG. 2. By means of the carriage 2, the pickup device can be shifted transversely (compare FIGS. 3 and 4) to lift the stack from the table 4 and to deposit it upon a conveyor tablet 5 designed to deposit the material in a press (see FIG. 11).

The pickup device 3 comprises a pair of clamping jaws or bars 7, 8 along each longitudinal edge of the table 4, the clamps comprising bars 7 of wood fixed to the underside of the support and lying outwardly of the outline of the table 4 for juxtaposition with the longitudinal edges 9 of the stack overhanging this table. The jaw 8 is swingable upon lowering of the support 3, in the counterclockwise sense and in the clockwise sense for the left-and right-hand jaws respectively to being the movable jaws 8 directly beneath the marginal portions 9 of the stack (see FIG. 3). The pneumatic cylinders 10 connected to the jaws 8 may thus be operated to draw the jaws 8 upwardly and clamp the marginal portion of the stack between each jaw 8 and the juxtaposed jaw 7.

In FIG. 7, I show an arrangement in which the cylinders for vertically shifting the jaws 8 are mounted upon a shaft 41 which is rotatable in trunions anchored to the support 3. An arm 42 is keyed to the shaft 41 and is displaceable by a further pneumatic cylinder 45, pivoted at 46 to the support and having a piston rod 44 articulated at 43 to arm 42. Thus, when the shaft 41 is rotated in the counterclockwise sense, the jaw 8 may be swung away from the stack 24 to clear the latter whenever the support 3 is raised and lowered.

The jaws 8 may be carried by L-shaped supports 53 mounted on the ends of piston rods 52 which are axially shiftable in cylinders 51 mounted by collars 50 of each shaft 41, 41a extending horizontally between the culinders 51. Members 51, 52, etc. represent the pneumatic devices shown diagrammatically in FIGS. 1 4. In FIG. 10, moreover. it can be seen that the carriage 2 is provided with a pair of pneumatic cylinders 60 whose piston rods 61 bear upon a plate 62 attached to an upright 63 carrying the support 3. FIG. 11 shows a multiplaten press 70 into which the conveyor tablet 5 can be introduced (dot-dash lines) to deposit the mat and the stack 24 carried thereon for final pressing, the conveyor tablet being withdrawn during deposit of the laminate on the press platen.

In operation, a stack of surface-finishing sheets is co]- lated upon the table 4 until the desired number is provided, whereupon the support 3 is lowered via cylinder 60 until the upper surface of the stack, here represented generally at I. Since the jaws 8 are in their outwardly swung positions during lowering of support 3, they do not engage the marginal portions 9 of the stacks. By actuations of pistons 45, however, the jaws 8 are swung inwardly to underlie the marginal portions 9, whereupon pistons 10 (see also FIGS. 8 and 9) are actuated to lift the jaws 8 and grip the marginal portions 9 between each pair ofjaws 7, 8. The support 3 is thereupon lifted (FIG. 3) by operation of cylinder 60 and the carriage 2 shifted to the right along rails 6 until the support 3 registers with a conveyor tablet S. The support 3 is thereupon lowered and. prior to clearing the conveyor tablet, the jaws 8 are swung outwardly to release the stack which can be processed as described previously (see FIG. 4).

I claim:

1. A system for the manipulation of a stack of surface-finishing layers applicable to a substrate in the formation of pressed board, comprising:

a table receiving said stack with opposite edges thereof overhanging said table;

horizontal track means extending from said table to a location horizontally spaced therefrom;

a carriage shiftable horizontally along said track means from a position overlying said table to said location;

a support vertically displaceable on said carriage;

respective clamps on said support along opposite edges thereof, said clamps each having a pair of relatively movable clamp jaws engageable with said overhanging edges of said stack on said table for displacement of said stack to said location, each of said clamps having a fixed jaw on said support and having a movable jaw swingable about a horizontal axis parallel to the overhanging edges of said stack, said fixed jaws lying in a common horizontal plane, a respective axle defining each of said axes and journaled on said support, a first fluid responsive device on said support for rotating each axle, and a second fluid-responsive device on each axle and carrying the respective movable jaw for shifting said movable jaw transversely and relative to the respective axle, said jaws each extending the full length of said stack; and

means providing a stack-receiving surface at said location.

2. The system defined in claim 1 wherein the jaws are wood bars. 

1. A system for the manipulation of a stack of surface-finishing layers applicable to a substrate in the formation of pressed board, comprising: a table receiving said stack with opposite edges thereof overhanging said table; horizontal track means extending from said table to a location horizontally spaced therefrom; a carriage shiftable horizontally along said track means from a position overlying said table to said location; a support vertically displaceable on said carriage; respective clamps on said support along opposite edges thereof, said clamps each having a pair of relatively movable clamp jaws engageable with said overhanging edges of said stack on said table for displacement of said stack to said location, each of said clamps having a fixed jaw on said support and having a movable jaw swingable about a horizontal axis parallel to the overhanging edges of said stack, said fixed jaws lying in a common horizontal plane, a respective axle defining each of said axes and journaled on said support, a first fluid responsive device on said support for rotating each axle, and a second fluid-responsive device on each axle and carrying the respective movable jaw for shifting said movable jaw transversely and relative to the respective axle, said jaws each extending the full length of said stack; and means providing a stack-receiving surface at said location.
 1. A system for the manipulation of a stack of surface-finishing layers applicable to a substrate in the formation of pressed board, comprising: a table receiving said stack with opposite edges thereof overhanging said table; horizontal track means extending from said table to a location horizontally spaced therefrom; a carriage shiftable horizontally along said track means from a position overlying said table to said location; a support vertically displaceable on said carriage; respective clamps on said support along opposite edges thereof, said clamps each having a pair of relatively movable clamp jaws engageable with said overhanging edges of said stack on said table for displacement of said stack to said location, each of said clamps having a fixed jaw on said support and having a movable jaw swingable about a horizontal axis parallel to the overhanging edges of said stack, said fixed jaws lying in a common horizontal plane, a respective axle defining each of said axes and journaled on said support, a first fluid responsive device on said support for rotating each axle, and a second fluid-responsive device on each axle and carrying the respective movable jaw for shifting said movable jaw transversely and relative to the respective axle, said jaws each extending the full length of said stack; and means providing a stack-receiving surface at said location. 